Solve (2x + 3) - (9x - 3)

Two customers went to a post office. first customer paid $12 for 14 and 5 envelopes the second paid 24.80 for 10 postcards and 15 envelopes. what is cost of each envelope?

Why is x= 4 a solution to the proportion 14/x 56/1 6

Calculate the total payback for a $3,500 loan at 8% annual interest with monthly payments for two years. show all of your steps. use the formula, m = pm(1 + m)^na/(1 + m)^na - 1, as needed.